UFC president Dana White has delivered a firm assessment on users of testosterone replacement therapy (TRT), insisting Anderson Silva is proof that fighters do not need to use it.

White admits he would love to ban TRT from the sport of MMA but cannot do so due to the way the sport is regulated.

"The way TRT works, it's 100 per cent legal. We're regulated by the government. The government allows these guys to do TRT," White said on ESPN's MMA Live.

The point was made to White that the UFC could soon have two high-profile champions on TRT, if Chael Sonnen beats Silva and Dan Henderson overcomes Jon Jones. Such a situation would be dangerous for the sport's image.

The argument for TRT is that it is legal, and it helps maintain normal testosterone levels, which tend to fall away as athletes get older. However, too often there have been examples of fighters who have taken their level way above the norm, effectively cheating.

"The way TRT works is, as you get older, your testosterone level drops. This replaces it. But the problem is you get guys going 'this much [gestures small amount] is good, so this much [gestures bigger amount] must be great.'

"You will find guys who will cheat even with the stuff that's legal.

"Anderson Silva, the best in the world, has broken every record in the UFC, he's 38 years old and he is not doing TRT. He's 100 per cent natural and he beats everybody.

"The bottom line is you don't need that junk. If you don't use stuff earlier in your career, you don't end up needing that junk."